1. Field of Invention
The present invention relates to footwear in general and to a method and apparatus for providing footwear with selectively extendable spikes in particular.
2. Description of Related Art
Traction is necessary for proper performance in many sports. For example, in the sport of golf, proper traction is required during full swing shots such as the tee shot and many fairway shots. Due to the grass covered surfaces on which golf is played, however, proper traction may be difficult. It is well known that the addition of spikes to the bottom of footwear for golf shoes helps to provide the necessary traction on such a surface. Such spikes were traditionally made of sharpened elongate metal projections.
Traditional metal spikes, however, suffered from the disadvantage of being damaging to some surfaces. In particular, the putting greens surfaces which have a significantly shorter grass length have been found to be damaged by metal spikes. Such metal spikes have been known to cause significant damage to putting greens by leaving holes and ridges in the ground as well as damaging the more delicate putting green grasses.
One solution to the above disadvantages of metal spikes has been to replace the traditional metal spikes with a spike insert comprising a plurality of plastic or rubber protrusions which are also known as the “soft spike”. Soft spikes have resulted in less damage to the putting greens surfaces. Accordingly, many golf courses have enacted rules prohibiting traditional metal spikes in favor of soft spikes. However, soft spikes have also reduced the traction provided to the golfer during full swing shots such as the tee shot. Therefore, while most recreational golfers now use soft spikes, many professional players continue to use metal spikes. The use of metal spikes for professional golf tournaments results in a significant amount of damage to the putting greens which is both costly to repair as well as obstructive to the play of later players.
Soft spikes have also not completely eliminated the damage occurring to golf course greens. As developers of soft spikes have attempted to increase the traction provided by soft spikes, the amount of damage these spikes inflicts on putting greens increases. In particular, it is known that metal spikes and newer designs of soft spikes results in damage to the structure of the grass making these grasses more susceptible to disease and other difficulties. Putting greens therefore require more fungicides, pesticides and water to ameliorate the damage caused to the grass from metal and soft spikes.
Previous attempts have been made to provide shoes with selectively extendable and retractable spikes. Examples of such shoes may be found in U.S. Pat. No. 4,821,434 to Chein, U.S. Pat. No. 6,058,627 to Violette et al., and U.S. Pat. No. 4,375,729 to Buchanen, III. However, such devices have not been suitable for use in a golf shoe as there are separated controls to extend or retract the spikes. Several of these controls are located in the toe of the sole where they may be prone to actuation during the follow-through of a golf swing.
Other attempts have required the user to activate the extension or retraction of the spikes from the sole of the shoe by manipulating a tab lever, screw or other device on the sole of the shoe itself. Examples of such devices may be found at U.S. Pat. No. 5,836,092 to Yarnell, U.S. Pat. No. 5,497,565 to Balgin, U.S. Pat. No. 6,389,714 to Mack, U.S. Pat. No. 5,956,870 to Grossman et al., U.S. Pat. No. 6,256,907 to Jordan et al., U.S. Pat. No. 5,732,482 to Remington et al., U.S. Pat. No. 5,870,838 to Khayat and U.S. Pat. No. 5,269,080 to Davis. Such devices have not been acceptable due to the need to bend down to extend or retract the spikes which may be difficult for some users and time consuming.